Will not start

JAYTEE972

MEMBER
2000 CHEVROLET EXPRESS
5.7L
V8
2WD
AUTOMATIC
310,000 MILES

Replaced fuel pump and fuel filter. Ran great for four months. Get in one morning it does not start. Does not start for three days then does and runs for four days. Does not start again. Change the plugs. Starts and runs for for a couple days. Then does not run for a couple days. Change the fuel filter again and starts right up. Runs for a day and has not started since. Tried spraying starter fluid. It will start, run for a couple seconds then shuts off. Only code is misfire on cylinder four but it has been reading that forever. Any help is appreciated.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,709 POSTS

Welcome to 2CarPros.

The idea that it will start with starting fluid indicates there is a fuel related issue. With that in mind, you need to start by checking fuel pressure at the fuel rail.

Here are two links. One deals with a cranks but no start and the other shows in general how to check fuel pressure.

https://www.2carpros.com/articles/car-cranks-but-wont-start

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

When you check the fuel pressure, here are the manufacturer's specs.

Key On Engine Off .................... 60-66 psi

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If you find there is no pressure, first confirm that you hear the pump turn on for a couple seconds when you first turn on the key. If you do not, check the fuse and fuel pump relay. The fuses are under the hood in the power distribution box. I attached a picture of the box, fuse locations, and two legends of what each fuses is for as well as where the fuel pump relay is located.

Make sure all fuses related to the pump and relay are good. Next, remove the fuel pump relay and first inspect the connections for corrosion or anything that could be preventing connection. If everything looks good, switch the relay with another relay in the box that has the same part number to see if that makes a difference.

If you fund the pressure is low, I suspect the sock on the fuel pump is plugging. Think about it. When the pump worked, it may have sucked up enough dirt to block the sock. Then, it sits and the dirt falls away from the sock and the engine runs again until the cycle happens again.

Now, if everything checks good, pressure, electrics. Let me know. At that point we will need to check the coolant temperature sensor to make sure it is working correctly. If it give a wrong temperature, the computer may be adjusting air fuel mixtures to compensate. If they are far enough off, it may load the engine with too much gas or not enough to run.

Let me know what you find. By the way, the coolant sensor I mentioned may or may not set a code. If it is sending a signal, right or wrong, the computer does not know it is wrong.

Take care and let me know what you find.

Joe

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